Add option to use STARTTLS for mails

/close #147

config.py.example

@@ -13,6 +13,7 @@ MAIL_HOST = "mail.example.com:465"
 MAIL_USER = "user" # set to "" for unauthenticated sending
 MAIL_PASSWORD = "password" # set to "" for unauthenticated sending
 MAIL_USE_TLS = True # should match the port in MAIL_HOST (if present there)
+MAIL_USE_STARTTLS = False # Usually, it's either this or SMTPS
 
 # (local) message queue (necessary)
 CELERY_BROKER_URL = "redis://localhost:6379/0"

utils.py

@@ -73,6 +73,7 @@ class MailManager:
         self.username = getattr(config, "MAIL_USER", "")
         self.password = getattr(config, "MAIL_PASSWORD", "")
         self.use_tls = getattr(config, "MAIL_USE_TLS", True)
+        self.use_starttls = getattr(config, "MAIL_USE_STARTTLS", False)
 
     def send(self, to_addr, subject, content, appendix=None):
         if (not self.active
@@ -91,6 +92,8 @@ class MailManager:
                 part["Content-Disposition"] = 'attachment; filename="{}"'.format(name)
                 msg.attach(part)
         server = (smtplib.SMTP_SSL if self.use_tls else smtplib.SMTP)(self.hostname)
+        if self.use_starttls:
+            server.starttls()
         if self.username not in [None, ""] and self.password not in [None, ""]:
             server.login(self.username, self.password)
         server.sendmail(self.from_addr, to_addr.split(","), msg.as_string())